Described below is a method for protecting a charging cable in a charging device for charging a traction battery of an electrically drivable vehicle and such a charging device.
Electrically drivable vehicles have a traction battery (rechargeable battery) which provides the electrical energy required for the vehicle operation. Discharged batteries need to be recharged by a charging device, if required. For this purpose, the traction battery of the electrically drivable vehicle and the charging device are electrically connected by a charging cable. Corresponding to the current-carrying capacity (electrical conductivity) of the charging cable, the charging cable has different line cross sections. For example, there are charging cables which have a current-carrying capacity of 13 A. Other charging cables have current-carrying capacities of 20 A, 32 A or 63 A, for example. In accordance with the standard IEC 62196-2, such charging cables are provided with electrical plugs which are configured as so-called type 2 plugs, for example. In accordance with this standard IEC 62196-2, these plugs also have the same geometric dimensions when they are intended for charging cables with different current-carrying capacities. Therefore, it is not possible to identify from the geometric dimensions of the plug the current-carrying capacity for which the charging cable connected to the plug is suitable.
In accordance with the standard IEC 61851-1, the current-carrying capacity of the charging cable is specified (coded) for these plugs by a resistance, which is connected between the “proximity” and “PE” contacts of the plug. In this case, a specific resistance value is associated with a specific current-carrying capacity of the charging cable.